As shown in Table 5 and visually summarized in Figure S1, in the EA sample, there was no evidence of interaction between parental divorce and offspring PRSALC on a multiplicative scale. However, the combined effect of parental divorce and PRSALC (i.e., OR = exp (0.34 + 0.29 + 0.07) = 2.01) was not equal to the sum of the individual effects, providing evidence of the presence of interaction on an additive scale (RERI = 2.01 − 1.41 − 1.33 + 1 = 0.27). A RERI of 0.27 indicates that the risk of developing AUD among individual exposed to parental divorce is 0.27 more with every unit increase in PRSALC than if there were no interaction between parental divorce and PRS. In the AA sample, there was no evidence of interaction between parental divorce and offspring PRSALC on a multiplicative or additive scale.
